We conducted a systematic review and meta-analysis of observational studies investigating the association between antibiotic exposure in infancy and risk of childhood overweight and obesity. Thirteen studies counting a total of 527,504 children were included in the systematic review and eight were included in meta-analyses. Exposure to antibiotics in infancy was associated with an increased odds ratio (OR) of childhood overweight and obesity (OR = 1.11 [95% CI 1.02-1.20]). Whereas exposure to one treatment only and exposure between 6 and 24 months were not associated with increased risk of childhood overweight and obesity, exposure to more than one treatment was associated with an OR of 1.24 (95% CI 1.09-1.43) and exposure within the first six months of life was associated with an OR of 1.20 (95% CI 1.04-1.37). In conclusion, antibiotic exposure in infancy is associated with a slightly increased risk of childhood overweight and obesity, mainly if children are exposed to repeated treatments or treatment within the first six months of life. It remains elusive whether this association is mediated via direct effects of antibiotics on the gut microbiota.